• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.724-728
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• 2001

In this study, the dielectric breakdown of epoxy composites used for transformers was experimented and then its data were simulated by Weibull distribution probability. The dielectric breakdown characteristics origin in epoxy composites were examined and various effects of dielectric breakdown on epoxy composites were also discussed. As a result, first of all, speaking of dielectric breakdown properties, the more hardener increased the stronger breakdown strength at low temperature because of cross-linked density by the virtue of ester radical. And the breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised, the electric field is concentrated, and the acceleration of electron and the growth of electron avalanche are early accomplished. In the case of filled specimens with treating silane, the breakdown strength become much higher since this suggests that silane coupling agent improves interfacial combination and relaxs electric field concentration. Finally, from the analysis of weibull distribution, it was confirmed that as the allowed breakdown probability was given by 0.1%, the applied field value needed to be under 21.5㎹/cm.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.779-783
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• 2002

The dielectric breakdown of epoxy composites used for transformers was experimented and then its data were simulated by Weibull distribution probability. As a result, first of all, speaking of dielectric breakdown properties, the more hardener increased the stronger breakdown strength at low temperature because of cross-linked density by the virtue of ester radical. And the breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised, the electric field is concentrated, and the acceleration of electron and the growth of electron avalanche are early accomplished. In the case of filled specimens with treating silane, the breakdown strength become much higher since this suggests that silane coupling agent improves interfacial combination and relaxs electric field concentration. Finally, from the analysis of weibull distribution, it was confirmed that as the allowed breakdown probability was given by 0.1%, the applied field value needed to be under 21.5MVcm.

• Korean Journal of Acupuncture
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• v.27 no.1
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• pp.107-123
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• 2010

Objective & Methods: The purpose of this study is to investigate the effects of Artemisiae Capillaris Herba herbal-acupuncture (ACH-HA) at GB34 (Yangleungchean) on hyperlipidemia induced with alloxan injection and high fat diet in rats. The author performed several experimental items to analyze the levels of various components and enzymes in serum, liver, as well as the histological changes of liver and aorta. Results: 1. ACH-HA solution increased the DPPH radical scavenging activity in rat liver cells. 2. ACH-HA at GB34 significantly decreased the levels of serum total cholesterol, low-density lipoprotein (LDL)-cholesterol, free cholesterol and atherogenic index (AI), while significantly increased the ratios of high-density lipoprotein (HDL)/total cholesterol and phospholipid/total cholesterol in hyperlipidemic rats. 3. ACH-HA at GB34 significantly decreased serum aspartate aminotransferase (AST) level in hyperlipidemic rats. 4. ACH-HA at GB34 significantly increased hepatic glutathione (GSH) activity in hyperlipidemic rats. Conclusion: From the above results, it is suggested that ACH-HA at GB34 may have therapeutic and preventive effects on hyperlipidemia.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.545-550
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• 2012

High Energy density metal powder has high melting point of oxide film. By this, the ignition source that can make a thermal effect of high-temperature during short time is needed to overcome ignition disturbance mechanism by oxide film. So effective ignition does not occurred with hydrocarbon ignitor, $H_2-O_2$ ignitor, high power laser. But steam plasma can be generate about 5000 K temperature field in short order. Because a steam plasma uses steam as the working gas, it is environmental-friendly and economical. Therefore in this study, we analyze steam plasma temperature field and radical species with optical emission spectroscopy method in order to apply steam plasma ignitor to metal combustion system and cloud particle ignition was identified in visual.

• Nutritional Sciences
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• v.4 no.2
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• pp.79-84
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• 2001

The influence of Rhodiola extract on tissue antioxidant status, plasma lipid levels, cholesterol contents of liver and fores were investigated in rats find oxidized linoleic acid. Groups of five-week old male Sprague-Dawley rats fed ad libitum with a diet containing 20% oxidized linoleic acid with or without 300 mg/kg body weight freeze-dried Rhodiola water extract. The antioxidant effect of dietary Rhodiola extract supplementation on the peroxidation potential of rats was investigated. The microsomal thiobarbiruric acid reactive substance (TBARS) contents were changed significantly by Rhodiola extract supplementation. Hepatic Catalase activities were increased in Rhodiola supplemented rats, whereas hepatic Manganese Superoxide Dismutase (MnSOD) or Copper Zinc Superoxide Dismutase (CuZnSOD) were not elevated. In addition, plasma cholesterol lowering effect was observed along with the stimulated excretion of cholesterol through the feces were observed with Rhodiola feeding. Supplementation with Rhodiola extract did not alter high density lipoprotein (HDL) cholesterol. These results support that Rhodiola extract may be effective in protection against oxidative stress, and prevention and treatment of blood dyslipidemia. It demonstntes that Rhodiola extract has a potential to exert anti-atherogenic properties antioxidative capacities .

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05b
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• pp.7-11
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• 2002

In this study, Au thin films were etched with a $Cl_2/Ar$ gas combination in an in an inductively coupled plasma. The etch properties were measured for different gas mixing ratios of $Cl_2/(Cl_2+Ar)$ while the other process conditions were fixed at rf power (700 W), dc bias voltage (150 V), and chamber pressure (15 mTorr). The highest etch rate of the Au thin film was 3500 $\AA/min$ and the selectivity of Au to $SiO_2$ was 4.38 at a $Cl_2/(Cl_2+Ar)$ gas mixing ratio of 0.2. The surface reaction of the etched Au thin films was investigated using x-ray photoelectron spectroscopy (XPS) analysis. There is Au-Cl bonding by chemical reaction between Cl and Au. During the etching of Au thin films in $Cl_2/Ar$ plasma, Au-Cl bond is formed, and these products can be removed by the physical bombardment of Ar ions. In addition, Optical emission spectroscopy (OES) were investigated to analyze radical density of Cl and Ar in plasma. The profile of etched Au investigated with scanning electron microscopy (SEM).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.11
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• pp.1464-1469
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• 2000

The effects of SiCl$_4$addition on flame structures have been studied in flame hydrolysis deposition (FHD) processes using Coherent anti-Stokes Raman spectroscopy (CARS) and planar laser induced fluorescence (PLIF) to measure temperatures and OH concentrations, respectively. The results demonstrate that even a small amount of SiCl$_4$ addition can change thermal and chemical structures of H$_2$/O$_2$ diffusion flames. When SiCl$_4$ is added to a flame temperature decreases in non-reacting zone due to the increases in both specific heat and density of the gas mixture, while flame temperature increase in particle formation zone due to the heat release through hydrolysis and oxidation reactions of SiCl$_4$. It is also found that OH concentration decreases dramatically in particle formation zone where temperatures increase. This can be attributed to consumption of oxidative species and generation of HCl during silica formation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.25.1-28
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• 2000

In this study, $Y_2O_3$ thin films were etched with inductively coupled plasma (ICP). The etch rate of $Y_2O_3$ , and the selectivity of $Y_2O_3$ to YMnO$_3$were investigated by varying $Cl_2$/($Cl_2$+Ar) gas mixing ratio. The maximum etch rate of $Y_2O_3$ , and the selectivity of $Y_2O_3$ to YMnO$_3$ were 302/min, and 2.4 at $Cl_2$/($Cl_2$+Ar) gas mixing ratio of 0.2 repetitively. In x-ray photoelectron spectroscopy (XPS) analysis, $Y_2O_3$ thin film was dominantly etched by Ar ion bombardment, and was assisted by chemical reaction of Cl radical. These results were confirmed by secondary ion mass spectroscopy(SIMS) analysis. YCl, and $YC_3$ existed at 126.03 a.m.u, and 192.3 a.m.u, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.2
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• pp.89-94
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• 2011

The cause of the thickness non-uniformity in the large area deposition of $SiO_2$ films by PECVD(Plasma Enhanced Chemical Vapor Deposition) was investigated by the plasma diagnostics. The spatial distribution of the plasma species in the chamber was obtained with DLP(Double Langmuir Probe) and the new-designed probe-type QMS(Quadrupole Mass Spectrometer). From the relationship between the spatial distribution of the plasma species and the depositing rate of the $SiO_2$ films, it was conformed that the non-uniform deposition of $SiO_2$ films was related with the spatial distribution of the oxygen radical density and electron temperature.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.108-111
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• 2000

FeS/FeS$_2$ minerals have been known to be potentially useful reductant to the removal of common organic contaminants in groundwater and soil. This research is aimed at improving our understanding of factors affecting the pathways and rates of reductive transformation of Hexachloroethane by catalytical iron minerals in natural system. Hexachloroethane is reduced by FeS/FeS$_2$ minerals under anaerobic condition to tetrachloroethylene and trichloroethylene with pentachloroethyl radical as the intermediate products. The kinetics of reductive transformations of the Hexachloroethane have been investigated in aqueous solution containing FeS, FeS$_2$. The proposed reduction mechanism for the adsorbed nitrobenzene involves the electron donor-acceptor complex as a precursor to electron transfer. The adsorbed Hexachloroethane undergo a series of electron transfer, proton transfer and dehydration to achieve complete reduction. It can be concluded that the reductive transformation reaction takes place at surface of iron-bearing minerals and is dependent on surface area and pH. Nitrobenzene reduction kinetics is affected by reductant type, surface area, pH, the surface site density, and the surface charge. FeS/FeS$_2$-mediated reductive dechlorination may be an important transformation pathway in natural systems.